Duplicate Media Finder - Duplicate Media Finder locates and deletes identical files and similar media
Tune Sweeper - Show duplicates in your Music library. Automatically select which duplicates to keep and delete based on your preferences. Remove duplicates with one-click from your iTunes or Music app library.
VisiPics - VisiPics does more than just look for identical files, it goes beyond checksums to look for similar...
Song Sergeant - Song Sergeant intelligently identifies and removes duplicates, renames inconsistently named artists...
Pixiple - Find images similar in pixel and/or metadata content
SongGenie - SongGenie analyzes, identifies and repairs your mp3 tags and names.